src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.virtual/src/org/graalvm/compiler/virtual/phases/ea/GraphEffectList.java

@@ -221,11 +221,11 @@
      * @param insertBefore
      *
      */
     public void replaceAtUsages(ValueNode node, ValueNode replacement, FixedNode insertBefore) {
         assert node != null && replacement != null : node + " " + replacement;
-        assert node.stamp(NodeView.DEFAULT).isCompatible(replacement.stamp(NodeView.DEFAULT)) : "Replacement node stamp not compatible " + node.stamp(NodeView.DEFAULT) + " vs " +
+        assert !node.hasUsages() || node.stamp(NodeView.DEFAULT).isCompatible(replacement.stamp(NodeView.DEFAULT)) : "Replacement node stamp not compatible " + node.stamp(NodeView.DEFAULT) + " vs " +
                         replacement.stamp(NodeView.DEFAULT);
         add("replace at usages", (graph, obsoleteNodes) -> {
             assert node.isAlive();
             ValueNode replacementNode = graph.addOrUniqueWithInputs(replacement);
             assert replacementNode.isAlive();

@@ -238,11 +238,11 @@
              * replacement has a less precise stamp than the original node. This can happen for
              * example in the context of read nodes and unguarded pi nodes where the pi will be used
              * to improve the stamp information of the read. Such a read might later be replaced
              * with a read with a less precise stamp.
              */
-            if (!node.stamp(NodeView.DEFAULT).equals(replacementNode.stamp(NodeView.DEFAULT))) {
+            if (node.hasUsages() && !node.stamp(NodeView.DEFAULT).equals(replacementNode.stamp(NodeView.DEFAULT))) {
                 replacementNode = graph.unique(new PiNode(replacementNode, node.stamp(NodeView.DEFAULT)));
             }
             node.replaceAtUsages(replacementNode);
             if (node instanceof FixedWithNextNode) {
                 GraphUtil.unlinkFixedNode((FixedWithNextNode) node);